Qualitatively, the effect of the projector is best understood in the case of
rotations: it takes a given, deformed HFB solution \(\mathinner {|{\Phi }\rangle }\) , rotates it in
space by Euler angles \(\Omega = (\alpha ,\beta ,\gamma )\)  and combines the results
to produce a rotationally-invariant wave function \(\mathinner {|{\Psi }\rangle }\) . Details on the
formalism, implementation and formal issues associated with projection
techniques can be found in many review articles and textbooks; see
[1]}, [2]}, [3]}, [4]}, [5]} for a short
selection. In the context of fission theory, projection techniques have been
applied only in a handful of cases, most notably to study the changes in the
potential energy surfaces caused by the projection-induced correlation energy
[6]}, [7]}, [8]}. One of the most promising applications
of projection has to do with the determination of the number of particles and
spin distributions of fission fragments, which we will discuss later.
